Singxer SU-1 with Aurender N100H

Possibly the Ayre output (did you use optical or Coax?) has less jitter than the USB 2 of the Aurender. Or the decoding of USB in the Holo Spring suffers from logic induced modulation - so it works better with the Singxer or a low jitter feed from the Ayre?

Anyway I don’t have hands on experience but others have reported and advised that the Holo Spring shines best with a Singxer or other type of bridge...

I wouldn't say it "needs" the Singxer to work properly since I use it with my Ayre CD player and it works great. I did an A/B test between the CD player and the Aurender using the same track of music however and the Ayre was noticeably better. 

Those I know with the Holo Spring DAC all say that it needs something like the Singxer to work properly - so I don’t think you can eliminate it.